OK, this is really bizarre. I can force on the apps that are marked as "On Demand" but I cannot install any of the mandatory automatic install apps.
Notice iPlayer, Photoshop, and Prime Video. All I installed from the Jamf School console.

Make sure the licenses are assigned for managed deployment, and that you actually have licenses in ASM/ABM for that app and the MDM in question.
If the licenses are assigned correctly check for network blocks as you have already renewed the VPP certificate.
Make sure the licenses are assigned for managed deployment, and that you actually have licenses in ASM/ABM for that app and the MDM in question.
If the licenses are assigned correctly check for network blocks as you have already renewed the VPP certificate.
I have assignable licenses. Just tried setting up another iPad for a different user and everything worked as it should.
This iPad, I tried blanking it and then enrolling it as me (rather than the teacher) but the apps still sit on Waiting for Licenses.
I'm going to try trashing the device and then putting it back. It seems that Jamf is stuck with this device only. Will report back.
OK, fixed it.
I had to remove the teacher from the group that gets the apps automatically installed, this cleared the pending apps list. Then I put them back in to the correct group and all the apps started to install. What a pain.
If anybody ever stumbles across this mess o a problem, here is the easy way to fix it:
1. Go to Apps - Inventory
2. click on the App you have trouble with
3. look on the right side where the options are
4. there is a “hidden” tiny gear-icon for troubleshooting options under the whole options menu
5. make sure you scrolled down enough
6. click on the tiny gear-icon
7. drop down menu appears (only viewable with all options if you scrolled down before - otherwise you wont see all options)
8. click on “retry app-installations that are stuck on “waiting for licenses”
9. be happy
wasted too much time on this and i am still wondering why they hide it like that and do not place those options under “advanced options” or something like that.